[Chris Hibner]

Without seeing the code, I'll throw out some irresponsible speculation.

Since the code is just passive, it sounds like there might be an issue with channel assignment. I would check to be sure that you're not trying to use the same channel for the motors and the encoders. Also check to see that your digital I/Os are configured properly. If you open the front panels for the encoder "get" blocks and the motor "set" blocks, you should be able to see if you're set up and sending the right commands.